1. Field of the Invention
The present invention relates to a mounting structure for a support shaft and an image generating apparatus, and more particularly, it relates to a mounting structure for a support shaft and an image generating apparatus each including a bearing.
2. Description of the Background Art
A mounting structure for a support shaft and an image generating apparatus each including a bearing for supporting a support shaft are known in general, as disclosed in Japanese Patent Laying-Open No. 05-168191 (1993), Japanese Utility Model Registration No. 2529981, Japanese Patent Laying-Open No. 2000-346043, Japanese Patent Laying-Open No. 08-042537 (1996), Japanese Patent Laying-Open No. 05-281848 (1993) and Japanese Patent No. 3812643, for example.
The aforementioned Japanese Patent Laying-Open No. 05-168191 discloses a bearing apparatus comprising a shaft (support shaft), a bearing body (bearing), a lower bearing support so arranged as to cover the bearing body and an upper bearing support so arranged as to cover the bearing body and the lower bearing support and so formed as to mesh with the lower bearing support. In this bearing apparatus described in Japanese Patent Laying-Open No. 05-168191, the upper bearing support meshing with the lower bearing support is so rotated and tightened toward the shaft as to clamp the lower bearing support thereby clamping the bearing body with the lower bearing support and fixing the shaft.
The aforementioned Japanese Utility Model Registration No. 2529981 discloses a shaft supporting structure comprising a rotating shaft (support shaft) including a tapered surface (chamfer), a ring-shaped outer block (bearing) and bearing balls. In the shaft supporting structure described in Japanese Utility Model Registration No. 2529981, the bearing balls are so arranged as to come into contact with the tapered surface of the rotating shaft and the inner side surface of the outer block.
The aforementioned Japanese Patent Laying-Open No. 2000-346043 discloses a rotating shaft support mechanism comprising a rotating shaft (support shaft) including a convex driving force transmitting portion provided on an end thereof and a rotating shaft support including a concave cut portion (bearing) provided on an end thereof. In the rotating shaft support mechanism described in Japanese Patent Laying-Open No. 2000-346043, the convex driving force transmitting portion of the rotating shaft is inserted into the concave cut portion of the rotating shaft support.
The aforementioned Japanese Patent Laying-Open No. 08-042537 discloses a member position control apparatus comprising a rotating shaft (support shaft) provided with a tapered surface (chamfer), an insertion member (bearing) and a bush nut. In the member position control apparatus described in Japanese Patent Laying-Open No. 08-042537, the bush nut comes into contact with the insertion member (bearing) and the tapered surface of the rotating shaft, thereby inhibiting the rotating shaft and the insertion member from backlash.
The aforementioned Japanese Patent Laying-Open No. 05-281848 discloses a developing apparatus (image generating apparatus) comprising a developing roller, two center shafts (support shafts) supporting both ends of the developing roller and two attachments. In the developing apparatus described in Japanese Patent Laying-Open No. 05-281848, the forward ends of the center shafts are in the form of triangular pyramids, while openings for receiving the center shafts are formed on both ends of the developing roller and tapered surfaces (contact portions) are formed inside the openings. The forward ends of the two center shafts support the tapered surfaces of the openings of the developing roller thereby supporting the developing roller, while the two attachments are pressed against both side shaft portions of the developing roller thereby inhibiting the developing roller from backlash.
The aforementioned Japanese Patent No. 3812643 discloses a transport follower roller mounting apparatus comprising a transport follower roller including shafts provided on both ends thereof and a bearing. In the transport follower roller mounting apparatus described in Japanese Patent No. 3812643, the bearing supports the shafts of the transport follower roller.
In the aforementioned bearing apparatus described in Japanese Patent Laying-Open No. 05-168191, however, the upper and lower bearing supports are provided independently of the bearing body (bearing) in order to fix the shaft, whereby the number of components is disadvantageously increased.
In the aforementioned shaft supporting structure described in Japanese Utility Model Registration No. 2529981, the bearing balls are provided independently of the ring-shaped outer block (bearing) in order to support the rotating shaft, whereby the number of components is disadvantageously increased.
In the aforementioned rotating shaft support mechanism described in Japanese Patent Laying-Open No. 2000-346043, the cut portion of the rotating shaft support is conceivably formed larger in size than the driving force transmitting portion of the rotating shaft in order to receive the driving force transmitting portion, whereby a clearance is formed between the driving force transmitting portion and the cut portion. Therefore, the rotating shaft disadvantageously causes backlash.
In the aforementioned member position control apparatus described in Japanese Patent Laying-Open No. 08-042537, the bush nut is provided independently of the insertion member (bearing) in order to inhibit the rotating shaft and the insertion member from backlash, whereby the number of components is disadvantageously increased.
In the aforementioned developing apparatus described in Japanese Patent Laying-Open No. 05-281848, the two attachments are provided independently of the two center shafts in order to suppress backlash resulting from rotation of the developing roller, whereby the number of components is disadvantageously increased.
In the aforementioned transport follower roller mounting apparatus described in Japanese Patent No. 3812643, a structure for supporting the shafts of the transport follower roller with the bearing is conceivably neither disclosed nor suggested, whereby the transport follower roller may disadvantageously cause backlash.